Framework: Fix GSM signal strength

Certain OEM gsm ril libs send back a bogus value for LTE signal
that causes SignalStrength.java to default to LTE and report
incorrect signal values.
Use prop value ro.telephony.ril.v3=signalstrength to get proper
GSM signal reading on certain devices.

Change-Id: Ibb23d7b3a2d21001ccbbc6ebfbdc3c5248f18cfc
Signed-off-by: dhacker29 <davidhackerdvm@gmail.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/telephony/java/android/telephony/SignalStrength.java b/telephony/java/android/telephony/SignalStrength.java
index 3f9fc0a..1951a32 100644
--- a/telephony/java/android/telephony/SignalStrength.java
+++ b/telephony/java/android/telephony/SignalStrength.java
@@ -19,6 +19,7 @@ package android.telephony;
 import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.os.SystemProperties;
 import android.util.Log;
 
 /**
@@ -435,6 +436,15 @@ public class SignalStrength implements Parcelable {
         return mLteCqi;
     }
 
+    public boolean needsOldRilFeature(String feature) {
+        String[] features = SystemProperties.get("ro.telephony.ril.v3", "").split(",");
+        for (String found: features) {
+            if (found.equals(feature))
+                return true;
+        }
+        return false;
+    }
+
     /**
      * Get signal level as an int from 0..4
      *
@@ -444,8 +454,9 @@ public class SignalStrength implements Parcelable {
         int level;
 
         if (isGsm) {
+            boolean oldRil = needsOldRilFeature("signalstrength");
             level = getLteLevel();
-            if (level == SIGNAL_STRENGTH_NONE_OR_UNKNOWN) {
+            if (level == SIGNAL_STRENGTH_NONE_OR_UNKNOWN || oldRil) {
                 level = getGsmLevel();
             }
         } else {
@@ -474,7 +485,8 @@ public class SignalStrength implements Parcelable {
     public int getAsuLevel() {
         int asuLevel;
         if (isGsm) {
-            if (getLteLevel() == SIGNAL_STRENGTH_NONE_OR_UNKNOWN) {
+            boolean oldRil = needsOldRilFeature("signalstrength");
+            if (getLteLevel() == SIGNAL_STRENGTH_NONE_OR_UNKNOWN || oldRil) {
                 asuLevel = getGsmAsuLevel();
             } else {
                 asuLevel = getLteAsuLevel();
@@ -506,7 +518,8 @@ public class SignalStrength implements Parcelable {
         int dBm;
 
         if(isGsm()) {
-            if (getLteLevel() == SIGNAL_STRENGTH_NONE_OR_UNKNOWN) {
+            boolean oldRil = needsOldRilFeature("signalstrength");
+            if (getLteLevel() == SIGNAL_STRENGTH_NONE_OR_UNKNOWN || oldRil) {
                 dBm = getGsmDbm();
             } else {
                 dBm = getLteDbm();